Customizing treatment in laser scar revision

Hypertrophic scar on the neck before (Left) and after (right) three 585nm pulsed dye laser (PDL) treatments.

Reduced energy and shorter pulse durations are more effective in laser scar revision than increased energy and longer pulses, according to Tina Alster, M.D., the founding director of the Washington Institute of Dermatologic Laser Surgery and a clinical professor of dermatology at Georgetown University Medical Center in Washington, D.C.

Discussing laser scar revision at the annual meeting of the Canadian Laser and Aesthetic Specialists Society, Dr. Alster says that scars are produced because of a deviation in the orderly pattern of healing. "An overzealous tissue response will create a hypertrophic or keloid scar," Dr. Alster explains. "Inadequate collagen replacement during wound healing will lead to an atrophic scar and prolonged inflammation and capillary permeation will result in an erythematous scar."

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There are stages, such as inflammation, proliferation, and maturation, in the wound healing process, which is typical after skin injury. A complex interplay between growth factors, cytokines, and extracellular matrix occurs and will determine if an unsightly scar develops, says Dr. Alster.

Various lasers, such as the pulsed dye laser, carbon dioxide laser, diode laser, as well as fractional lasers, both ablative and non ablative, can be employed in the treatment of surgical scars, keloid scars, and burn scars, says Dr. Alster, adding the key is to individualize and customize the lasers to the characteristics of the scar.

In the era before fractional technology was available, when high-energy pulsed CO₂ lasers were used to treat atrophic acne scars, the resultant post-treatment recovery was long and resulted in prolonged redness, notes Dr. Alster.

NEXT: Optimal techniques

Optimal techniques

Tina Alster, M.D.It is critical to avoid overlapping spots or scans when using lasers, according to Dr. Alster. "If you treat on top of an area that has already been irradiated, you are treating an already-changed target," she says, adding that "It is important to place laser spots side-by-side with minimal to no overlap in order to avoid excessive injury to the area and reduce the risk of post-inflammatory hyperpigmentation."

Dr. Alster says that she routinely uses a 4.5 to 5.0 J/cm² fluence when treating an erythematous, keloid or hypertrophic scar and does not use large spot sizes.

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"Lower energies and shorter pulse durations work better," says Dr. Alster. "If you use fluences of 6, 7, and 8 J/ cm² , you are using excessively high energies that will not produce optimal clinical results."

Performing laser scar revision at appropriate intervals is a necessary step in treating scars, with Dr. Alster suggesting that there be at least a six-week interval between treatments and noting that intervals of two or three weeks between treatments are insufficient.

"Patients want a quick, clinical response, but performing treatments at insufficient time intervals often results in greater risk of post-inflammatory hyperpigmentation or scars that remain erythematous because they are still inflamed from the previous treatment," says Dr. Alster. "For that reason, I prefer to wait at least six to wait eight weeks between laser treatments."

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The adjunctive use of intralesional corticosteroids with laser therapy has not demonstrated significant added benefit. In one study, the use of 585 nm-pulsed dye laser with and without intralesional corticosteroids in the treatment of hypertrophic inframammary scars resulted in a non-significant difference between the two types of treatments.¹

Similarly, a more recent study found the use of a pulsed dye laser with or without intralesional triamcinolone are both moderately effective in treating keloid scars.²

NEXT: Laser scar revision on patients who have dark skin

Another consideration in laser scar revision is treating patients who have darker skin types. "It is necessary to wait between [laser scar] treatments because there is more inflammation," says Dr. Alster. "We want all laser-related inflammation to subside before the next treatment. I typically apply the same laser parameters at each treatment session-you can't go wrong by going too low [in fluence]."

A bruise does not necessarily develop with the use of low fluences in laser scar revision, so clinicians should not look for the development of a bruise as a sign of treatment efficacy, says Dr. Alster.

To optimize treatment with a laser and to avoid potential dermatitis, clinicians should advise their patients to avoid putting active topical products (for example, vitamin C or retinoic/glycolic acid) on their skin immediately after laser therapy, according to Dr. Alster.

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The workhorse in Dr. Alster's practice is the pulsed dye laser. "For the past 25 years, I have used it for a whole host of conditions," she says. "In addition to vascular lesions, I routinely use the PDL for hypertrophic and erythematous scars, keloids, excorations, and striae."

Lasers that offer greater specificity and target the vasculature are appropriate for scar revision. "A laser that just puts heat in the dermis doesn't affect scars the same way that a vascular laser does," she says, noting a pulsed dye laser is suitable for laser scar revision because it offers specificity necessary to diminish the appearance of a scar.

In terms of when to start scar revision laser treatment for post-operative scars, Dr. Alster says therapy can be initiated earlier on if a patient is prone to developing scars. "It may be better to treat as soon as the sutures are removed," she says.

Dr. Alster has no relevant disclosures.

References:

            ¹ Tanzi  EL, Williams CM, Alster TS. Treatment of facial rhytides with a nonablative, 1,450-nm diode laser: a controlled, clinical and histologic study. Dermatol Surg. 2003;29(2):124-8.

            ² Stephanides S, Rai S, August P, Ferguson J, Madan V. Treatment of refractory keloids with pulsed dye laser alone and with rotational pulsed dye   laser and intralesional corticosteroids: A retrospective case series. Laser Ther. 2011;20(4):279-86.